This invention relates to the end structure for a carton to prevent sifting out and escape of finely divided contents such as flour. The packaging industry has made a considerable effort to improve the sift-proof integrity of its inexpensive paperboard cartons. These are die cut from a one piece blank and formed with a manufacturer's joint into a tube which is shipped flat to the packaging customer and erected and filled and closed by him on appropriate packaging machinery.
One procedure which has been developed in the industry is called the reverse-fold sequence in which the flaps of adjacent front, back and side panels are more or less sequentially folded over to form the end as distinguished from the procedure in which opposite panels are folded at the same time and never sequentially with respect to individual adjacent panels.
The specific procedures which have been developed have their limitations and are subject to constant improvement.
It is accordingly the general object of this invention to provide a sift-proof end structure for a carton which is an improvement over what has previously been done and produced in the art.